is this the only color on sale

It appears so but hopefully Gevalia will consider producing it in other colors. I have an older model with a hinged attached porcelain top in forest green which I still use and would prefer this color to the cream. But I do very much like the cream canister that they are still offering.

is this made of porcellin?

What's the knob height and ease of use?

Knob looks small and low, so I'm wondering how easy it is to break the silicon seal and lift the lid using this knob? Looks like it would be a struggle, maybe even chipping the canister in the process? Is the white canister easier to open? (I don't think it looks as elegant as the cream canister, though.)

The knob height is about 1 inch and is easily removed from the canister. This is my experience with the one I purchased which would make me purchase another if I needed it. This is for the cream canister. Not sure about the white one.